The invention is an improvement over the couplng shown in U.S. Pat. No. 3,434,092 issued Mar. 18, 1969 to R. J. Brown et al. In a vacuum cleaner of this type, the hose serves not only to convey air but also to pull the cleaner over the floor, and the mechanical force required is transmitted from the hose through the coupling to the cleaner. The hose is connected to the coupling by being clamped between a metal sleeve and a plastic part, the latter carrying electric contacts which protrude with clearance through apertures in an outer metal shell which carries latches engaging abutments on the cleaner. Should the aforesaid mechanical force cause the connection between the hose and the coupling to loosen, it could result in the plastic part and the outer metal shell shifting relative to each other, thereby causing the electric contacts to touch the edges of the apertures in the metal shell to cause a short circuit.